Liquid fuel burner system and fuel control



- Feb. 18, 1969 w. D. NUTTEN ET AL 3,423,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Sheet Original Filed May 19, 1964 A HM m w 7 m mu 5 W M Q m w M M m %.w\ N. MwdATh w 8* 5 A & W a w 5 fi W M M 11 Q w u m NY fi I l 1 l l l l I ||NIPJW Q m w 1 1 1|Y:% o w QM! m W MN Q 'L I kw ww NL Feb. 18, 1969 w. D. NUTTEN ET AL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Original iled May 19, 1964 Y Sheet 2 of 11 INVENTORS WARREN a Norm/v & BY Emu/mp 6. Ema/Pa Maw ATTORNEY Sheet W. D. NUTTEN ET AL LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Feb. 18, 1969 Original Filed May 19, 1964 VNN NW. kw v d RN. @VM. QM. NQ m mmw N Feb. 18, 1969 w. D. NUTTENI-ETAL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Original Filed May 19, 1964 Sheet of 11 378a INVENTORS 377a W/imm/ A Alarm/v 61 fimmxw C. pH/LL/PS 383a flrropA/ y Feb. 18, 1969 w, NUTTEN ET AL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Original Filed May 19, 1964 Sheet L of 11 INVENTORS Mama/v D. A/UTTEA/ &

BY 5mm 120 6 PM 1 [/25 F a a H TTOR/V'y Feb. 18, 1969 w. D. NUTTEN ET AL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Original Filed May 19, 1964 Sheet 9 of 11 INVENTORS h/Akkw 0. A/urns/v & BY 1552mm (I. H/LL/PS 6. Arrow/5y Feb. 18, 1969 w. D. NUTTEN ET AL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL 7 Original Filed May 19, 1964 Sheet [4 of 11 INVENTORS WAPQEA/ 0. lVZ/TTEA/ 6;

Tram/[y Feb. 18, 1969 w. D. NUTTEN ET AL 3,428,406

LIQUID FUEL BURNER SYSTEM AND FUEL CONTRCL Original Filed May 19, 1964 Sheet 0f ll MIAMI/m A A 775 I 7580 )ig' I 7320 United States Patent 3,428,406 LIQUID FUEL BURNER SYSTEM AND FUEL CONTROL Warren D. Nutten and Bernard C. Phillips, Toledo, Ohio, assignors to The Tillotson Manufacturing Company, Toledo, Ohio, a corporation of Ohio Original application May 19, 1964, Ser. No. 368,475, now Patent No. 3,377,024, dated Apr. 9, 1968. Divided and this application Feb. 19, 1968, Ser. No. 706,451 US. Cl. 431-12 7 Claims Int. Cl. F2311 1/00; F16k 31/12, 31/36 ABSTRACT OF THE DISCLOSURE Fuel pressure used with an aspirating type fuel nozzle controls actuation of a diaphragm in a chamber to regulate a valve in a passage controlling fuel flow to the nozzle.

This is a division of application Ser. No. 368,475, filed May 19, 1964, now Patent No. 3,377,024.

This invention relates to a liquid fuel combustion burner sysem and control and more particularly to a fuel control for a combustion burner of a character wherein liquid hydrocarbon fuel is aspirated under the influence of a high velocity air stream into a fuel and air mixing zone.

Liquid hydrocarbon fuels, such as fuel oils, have been used in fuel burners of a character wherein an air stream is utilized to aspirate fuel from a fuel bowl equipped with a float-controlled valve and supplied with liquid fuel from a fuel supply tank located above the burner whereby the fuel is elevated or lifted from the float or fuel bowl by reduced pressure or suction develoed by an air stream and the liquid fuel mixed with the air to provide a combustible mixture. Arrangements of this character have been used in burners for salamanders and for similar uses.

In combustion burners of this character the fuel supply tank must necessarily be disposed above the float bowl because of lack of control of fuel feed for a fuel supply disposed below the burner. In such installations the fuel tank is disposed above the burner providing a gravity or pressure head of liquid fuel operative against the float-controlled valve arrangement. With such arrangement, the float control is subservient in a measure to variations in the level of the fuel in the float bowl resulting in variations in fuel delivery to the burner nozzle. As the fuel bowl must be vented, it presents a serious fire hazard and, furthermore, the fuel bowl must be maintained stationary and in an upright position in order to function.

The present invention embraces a method of controlling delivery of liquid fuel to a combustion burner from a fuel tank which includes esablishing an air stream and flowing fuel from a flexible walled chamber to the combustion zone of the burner by aspiration set up by the air stream, normally biasing a fuel inlet valve in a fuel duct from a fuel supply to closed position, and opening the inlet valve by movement of the flexible wall under the influence of differential pressures to effect delivery of fuel to the burner nozzle.

The invention embraces a method of controlling delivery of liquid fuel to the combustion zone of a combustion burner involving the use of a pressure responsive mem ber controlling a fuel inlet valve whereby fuel is delivered to the burner when differential pressures are developed of a magnitude affecting the member to overcome a biasing force normally closing the inlet valve whereby the said control is effective irrespective of whether the fuel supply is maintained above or below the combustion burner.

F a C Another object of the invention resides in a control for liquid fuel delivered to a combustion burner wherein the control is influenced by differential pressure set up by an air stream into which the fuel is delivered and wherein means normally biasing a fuel inlet valve to closed position must be overcome by differential pressure before fuel is delivered to the combustion zone.

Another object of the invention resides in the provision of a pressure responsive arrangement for controlling delivery of liquid fuel into an air stream of a combustion burner wherein a diaphragm actuated by differential pressures contorls a fuel inlet valve, the arrangement including means normally biasing the inlet valve closed whereby impairment of operating pressure or fracture of the diaphragm results in instant closure of the fuel inlet valve to thereby reduce the hazard of fire.

Another object of the invention resides in the provision of a differential pressure control of the delivery of fuel by aspiration to a combustion zone of a combustion burner which is effective irrespective of the relative position of the fuel tank with respect to the burner.

Another object of the invention is the provision of a pressure responsive control system particularly usable for controlling delivery of liquid fuel to a mixing region of a combustion burner wherein the system includes dual pressure responsive devices arranged in sequential relation and each provided with a diaphragm actuated fuel valve for controlling fuel fiow under the influence of presure responsive diaphragms providing protection against fire hazard and wherein impairment or failure of one device effectively interrupts fuel flow.

Another object of the invention is the provision of a pressure responsive control unit for connection between a fuel supply and a fuel delivery nozzle of a combustion burner wherein the unit is of compact construction embodying dual valves, each controlled independently by a pressure responsive device, the valves being arranged in sequence and each provided with means effective to close an inlet valve upon failure or impairment of the pressure responsive means.

Another object of the invention resides in a pressure responsive control unit associated with or embodying an effective fuel filter for straining the fuel prior to its delivery through the unit to minimize the liability of foreign matter impairing the closing of the inlet valve or valves of the control unit.

Another object of the invention resides in a single control unit or dual units in sequential relation each embodying a pressure responsive diaphragm arranged to be actuated by pressure of an air stream delivered to the combustion zone of the burner in combination with means for positively interrupting fuel flow from a supply upon failure of air pressure or impairment or fracture of a diaphragm.

Another object of the invention is the provision of a differential pressure actuated unit for controlling flow of liquid fuel to an aspirated nozzle of a combustion burner arranged to automatically interrupt fuel flow upon mipairment or failure of aspiration at the burner nozzle.

Further objects and advantages are Within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a semi-schematic view, partly in section, of a liquid fuel feed and air mixing arrangement for a combustion burner embodying a form of differential pressure-actuated fuel flow control means of the invention;

FIGURE 2 is a sectional view taken substantially on the line 22 of FIGURE 1;

FIGURE 3 is an elevational view of the fuel control means shown in FIGURE 1;

FIGURE 4 is a top plan view of the arrangement shown in FIGURE 3;

FIGURE 5 is a sectional view taken substantially on the line 55 of FIGURE 4;

FIGURE 6 is a schematic sectional view illustrating the components of the type of unit shown in FIGURE 5;

FIGURE 7 is a sectional view illustrating a liquid fuel flow control unit of the invention embodying one pressure responsive means and control valve;

FIGURE 8 is a top plan view, on a reduced scale, of the construction shown in FIGURE 7;

FIGURE 9 is a fragmentary detail sectional view illustrating a fuel inlet valve and diaphragm control means therefor;

FIGURE 10 is a top plan view of a form of duel control mechanism embodying a fuel strainer;

FIGURE 11 is a sectional view illustrating the dual fuel control mechanism embodying a fuel filter construction shown in FIGURE 10;

FIGURE 12 is a fragmentary sectional view taken substantially on the line 1212 of FIGURE 10;

FIGURE 13 is a sectional view taken substantially on the line 13-13 of FIGURE 11;

FIGURE 14 is a top plan view showing an arrangement of dual fuel control mechanisms within a housing and a fuel filter construction;

FIGURE 15 is a longitudinal sectional view of the arrangement shown in FIGURE 14;

FIGURE 16 is a sectional view illustrating a modification of the fuel fiow control arrangement of FIGURE 15;

FIGURE 17 is a top plan view illustrating a modified form of fuel flow control unit of the invention;

FIGURE 18 is a vertical sectional view of the construction shown in FIGURE 17;

FIGURE 19 is a sectional view illustrating a modified form of fuel flow control Illlt;

FIGURE 20 is a detail sectional view illustrating a form of biasing means for a fuel inlet control valve;

FIGURE 21 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 2 illustrates another form of fuel flow control mechanism;

FIGURE 23 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 24 is a detail view taken substantially on the line 2424 of FIGURE 23;

FIGURE 25 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 26 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 27 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 28 is a sectional view illustrating another form of fuel flow control mechanism;

FIGURE 29 is a fragmentary detail view of a portion of the construction illustrated in FIGURE 28;

FIGURE 30 is a sectional view illustrating another modification of fuel flow control mechanism;

FIGURE 31 is a sectional view illustrating a further modification of fuel flow control mechanism;

FIGURE 32 is a semi-schematic sectional view illustrating an arrangement wherein super atmospheric pressure is utilized for actuating a fuel flow control mechanism, and

FIGURE 33 is a semi-schematic sectional view illustrating an arrangement of dual control units of the character shown in FIGURE 32.

The method and apparatus of the invention are particularly adapted for controlling flow of liquid fuel to a delivery nozzle of a combustion burner of a type wherein the fuel is aspirated into an air stream and the mixture ignited in a combustion zone of a burner, such as burners used in salamanders, oil fired burners used with heating furnaces and the like.

Referring to the drawings in detail and initially to FIGURES 1 and 2, there is illustrated a burner construction which may be associated with a combustion chamber or zone defined by a member 10, a circular bracket 12 of conventional construction being employed for mounting the burner to the member 10. In the arrangement illustrated in FIGURE 1. the burner is inclusive of a generally cylindrically-shaped member 16 having a hollow sleeve portion 18, the forward end of the sleeve being secured by screws 14 to the bracket 12. Disposed at the rear of the member 16 is a vane type rotary pump comprising a housing 20 having an interior circular chamber 22. R0- tatably mounted in the chamber 22 on an axis eccentric to the axis of the chamber 22 is a rotor 24 provided with radial slots 26 in which are disposed relatively slidable vanes 28. The rotor 24 is fixedly secured upon a shaft 30 of an electrically energizable motor 32.

- The member 20 is provided with an opening or port 34 providing for the entrance of air into the pump chamber 22. The member 16 is provided with an outlet duct 36 which is in communication with the pump chamber 22 and through which air, which is compressed by rotation of the pump rotor 24, is delivered to a chamber 38 arranged axially in the member 16. Arranged axially of the chamber 38 is a fuel delivery nozzle 40 through which fuel is delivered into an ignition zone 42 defined by the sleeve 18, the burning mixture being delivered into a combustion zone or region 44.

In the embodiment illustrated, a member 46 surrounds the fuel delivery nozzle 40 and has its interior surface 47 ofventuri configuration providing a restricted zone or band 48 adjacent the outlet of the nozzle 40. In the emhodiment illustrated, fuel is aspirated through the nozzle 40 by the velocity of the air stream passing through the annular restricted space 50 at the choke band of the venturiv which sets up a reduced or subatmospheric pressure at the nozzle outlet.

Fuel is supplied from a tank or receptacle 54 through a conduit or pipe 56, a manually operable valve 58 being provided in the conduit 56 for cutting off the fuel supply when desired. The conduit 56 conveys fuel to the inlet side of a pressure actuated fuel control mechanism or unit 60 hereinafter described in detail. Fuel is conveyed from the outlet of the unit 60 through a fitting 61, pipe 62 and interconnecting channels 64 and 66 in member 16 to the nozzle 40 for delivery through the nozzle.

Fuel aspirated from the nozzle 40 is initially mixed with air delivered from the air pump chamber 22 flowing at substantial velocity through the annular space 5'0 of the venturi, and additional air is mixed with the fuel through openings 68 formed in the sleeve portion 18 of the member 16 to provide the requisite amount of air for satisfactory combustion in zones 42 and 44.

Surrounding the burner construction and the motor 32 is a housing 70 of generally cylindrical shape which is secured to an annular bracket 72 mounted by the motor 32, screws 73 securing the housing to the bracket.

The forward portion of the housing 70 is flared inwardly and the terminal portion thereof secured to the sleeve 18 by screws 74. Mounted upon the rear end of the motor shaft 30 is an impeller or fan 76 which is rotated by the motor and provides a moving air stream along the exterior of the motor 32 and through the openings 68. A filter or screen 80 is scoured to the rear end of the housing 70 for filtering the air moved by the impeller 76 and the air compressed in the pump chamber 22.

A spark plug 82 is threaded into an opening in the member 16, the spark plug being connected by a conductor '83 with an ignition coil or transformer 84 supplied with alternating current in a conventional manner. The conductor 83 extends through a rubber grommet 86 mounted in an opening in the wall of the housing 70. The

spark plug ignites the mixture of liquid fuel and air in the zone 42 and the burning mixture enters the combustion zone 44 and is completely burned therein. The pipe 62 extends through a grommet 65 mounted in an opening in the housing 70.

It is to he understood that other forms of air and fuel mixing arrangements may be used in lieu of the venturi construction 47.

For example, a conventional type of fuel and air aspirating mixing nozzle may be employed. The burner arrangement described is of a character for burning conventional liquid hydrocarbon fuels such as fuel oils for conventional combustion burners.

One form of pressure actuated valve arrangement for controlling flow of liquid fuel to the burner is illustrated in FIGURES 3, 4 and 5 and a schematic sectional view of this construction is illustrated in FIGURE 6. The control arrangement in. this form embodies dual fuel flow control valves and dual pressure actuated diaphragms for controlling the valves. The control arrangement 60 is inclusive of a body member or housing 90 of generally cylindrical shape. The housing is formed with a substantially annular portion 91 defining a fuel chamber 98, a planar surface 92 of the annular portion providing a seat for an annular gasket 93, a flexible diaphragm 94 engaging the gasket 93 as shown in FIGURE 5.

A circular cover plate 95 is secured to the body 90 by screws 96 threaded into suitable openings in the body 90. The diaphragm 94, which is of flexible impervious material forms a flexible wall of the fuel chamber 98. The central region of the cover 95 is recessed or shaped to provide a space or air chamber 99 to facilitate flexing movements of the diaphragm 94, the space 99 being vented to the atmosphere through a vent opening 100. The diaphragm is flanked at each side by relatively thin circular reinforcing plates 101 fashioned of thin metal or plastic material.

The diaphragm 94 and the reinforcing plates 101 are formed with aligned central openings to receive a shank of a rivet 102, the head 103 of the rivet extending into the fuel chamber 98. The diaphragm 94 may be fashioned of fabric impregnated or coated with synthetic rubber or may be formed of resinous material of a character that does not deteriorate on contact with hydrocarbon fuels. The housing 90 is provided with a boss portion 104 provided with a threaded inlet bore 105 to receive a fitting 106, shown in FIGURE 1, for connecting the conduit 56 with the control unit 60-. The threaded bore 105 in the boss 104 is connected with a duct or channel 107.

Referring particularly to FIGURES 4 and 5 and to the semi-schematic view of FIGURE 6, the body 90 is provided with a threaded bore to accommodate a threaded sleeve or valve cage 109 in which is slidably disposed an inlet valve or valve member 110 provided with a coneshaped valve portion 111 which seats in an annular seat member 112 mounted in the upper end of the valve cage 109. An annular sealing gasket 114 is disposed adjacent the inner end of the valve cage 109 to provide a seal. The body portion of the valve 110 is of polygonally-shaped cross-section, such as triangular or square shape, to facilitate flow of liquid fuel past the valve.

Disposed in the chamber 98 is a lever 116 fulcrumed upon a pin or shaft 117 carried by the body 90. The long arm 1.18 of the lever is adapted to be engaged by the button or head 103 of the rivet 102, the short arm 120 of the lever being engageable with the valve member 110.

The lower end of the valve body is provided with a recess forming a tenon portion 121 and the short arm 120 of the lever is forked or bifurcated to straddle the tenon portion, the recess providing a head 122.

This construction provides a positive connection between the lever and the valve member so that upward movement of the diaphragm 94, as viewed in FIGURE 5, effects counterclockwise movement of the lever 116 moving the valve portion 111 away from the seat 112 whereby fuel will flow from the inlet duct 107 through the port in the valve seat 112 into the chamber 98. A resilient member or spring 124 arranged between a wall of the chamber 98 and the lever arm 1.18 exerts a force upon the lever normally biasing the inlet valve 111 toward the valve seat 112 to interrupt fuel flow into the chamber 98.

The semi-schematic sectional view of FIGURE 6 particularly illustrates the fuel inlet and fuel filter construcstruction. The housing 90 is provided with a bore having a threaded portion 128 which receives a threaded plug 130. The plug 130 is provided with an interior bore 131 in which is telescoped a cylindrically-shaped screen or filter 132, the end of the screen being closed by a cupshaped member 133. The plug 130 is provided with a counterbore 134 and a peripheral recess 135.

A plurality of circumferentially spaced radial openings 136 establish communication between the peripheral recess and the counterbore 134. The peripheral recess 135 is in communication with the fuel inlet passage 107 shown in FIGURES 5 and 6 for conveying fuel to the port 115 adjacent the valve member 110.

The filter 132 illustrated herein is of fine mesh copper screen to filter foreign particles out of fuel, but it is to be understood that other types of filter may be used such as wool or other fibrous material.

The arrangement shown in FIGURES 3 through 6 is inclusive of a second valve construction arranged to be actuated by differential pressure set up by the air stream passing through the restricted passage 50 of the venturi 47 shown in FIGURE 1. The housing 90 is provided with a substantially annular portion 138 defining a second fuel chamber 150, an upper planar surface 140 of portion 138 forming a seat for a gasket 141. Engaging the gasket 141 is a second diaphragm 142 of the same character as the diaphragm 94, the diaphragm 142 forming a wall of chamber A second closure plate 144 engages the diaphragm 142 and is secured to the housing by screws 146 threaded into suitable openings in the housing 90.

The central region of the closure 144 is shaped to provide a space 148 to accommodate flexing movements of the diaphragm 142. The closure 144 is vented to the atmosphere by a vent opening 149. Disposed centrally of the diaphragm 142 is a rivet 152 which extends through reinforcing discs 153 arranged at each side of the diaphragm. Fulcrumed upon a pin 154 in chamber 150 is a second lever 156, one end of the lever being arranged to be engaged by a head 157 on the rivet 152.

The short arm of the lever is bifurcated to straddle a tenon 158 formed on a valve body 160, the latter being of the same character as the valve member 110. The valve member 160 is slidably mounted within a valve cage or guide means 162 threaded into a bore in the housing 90. Arranged in the cage 162 is an annular valve seat 164 providing a port 165 into which extends a cone-shaped valve portion 166 of the valve member 160 to control fuel flow through the port 165. A sealing gasket 168 is disposed at the end of the valve cage 162. The port 165 is in communication with the chamber 98 by a passage 170.

As shown in FIGURE 6, the housing is provided with a threaded bore 172 providing an outlet which is adapted to accommodate the fitting 61 shown in FIGURE 1. The bore 172 is in communication with the chamber 148 through interconnecting channels 174 and 175. The lever 156 is biased in a direction to close the valve 166 by an expansive coil spring 159 in the same manner that the spring 124 biases the valve 111 toward closed position.

The operation of the control unit 60 with a burner arrangement as shown in FIGURE 1 is as follows: The motor 32, driving the air pump rotor 24 and the impeller 76, is energized simultaneously with the energization of the transformer 34 to initiate a spark between the points of the ignition plug 82.

The operation or rotation of the pump rotor 24 develops air under pressure in the pump outlet passage 36 providing a high velocity air stream through the restricted passage or choke band 50 of the venturi 47 developing a subatmospheric or reduced pressure at the region of the fuel delivery orifice or nozzle 40.

The subatmospheric pressure or aspiration developed at the burner nozzle 40 is communicated through the channels 66, 64, the pipe 62 and fitting 61 is transmitted through the interconnecting channels 174 and 175 to the chamber 150. Due to the differential pressures existent on opposite sides of the diaphragm 142, the atmospheric pressure in chamber 148 flexes the diaphragm 142 downwardly, as viewed in FIGURE 5, to effect counterclockwise movement of the lever 156 about the fulcrum 154 through engagement of the button 157 on the diaphragm with the long arm of the lever 156.

The area of the diaphragm 142 is sufficient whereby the atmospheric pressure acting on the diaphragm, when subatmospheric pressure exists in the chamber 150, overcomes the biasing pressure of the spring 159 to effect counterclockwise movement of the lever 156, the lever 156 multiplying the force effective to open the valve 160. The short arm of the lever 156 withdraws the valve body 160 upwardly to move the valve portion 166 out of engagement with the seat 164 to establish communication between the chamber 150 through the port 165 and passage .170 with the chamber 98 adjacent the diaphragm 94.

The areas of the diaphragm 142 and 94 subject to differential pressures are substantially the same. When subatmospheric pressure is impressed in the chamber 98 by the opening of the valve 160, the diaphragm 94, as viewed in FIGURE is flexed upwardly under the influence of atmospheric pressure in the space 99. This movement causes the lever 116 to be swung in a counterclockwise direction, the button 1413 on the diaphragm being engaged with the arm 118 of the lever 116. In this manner, the reduced pressure existent in the chamber 150 is also existent in the chamber 98 when the valve 160 is in open or partially open position.

As the diaphragm M is flexed upwardly, the valve 110, connected with the short arm 120 of the lever 116, is moved downwardly moving the valve portion 111 out of the engagement with its seat 112 to open the ort 115 and admit fuel into the chamber 98 from the tank 54 through the pipe 56, fitting 106, channel 167 to the in terior of the plug 130, through the filter or screen 132 and passage 115 past the valve 11. As shown in FIGURE 1, the fuel conveying tube 56 is connected with a manually operated valve 58, the latter being in normally open position to establish communication between the fuel tank and the tube 56.

As both valves 110 and 160 are thus opened through the impression of subatmospheric pressures in the chambers 150 and 98, fuel flows from the supply through the tube 56 into the inlet 105, through the filter screen 132 and passage 107, through the port 115, past the valve body 110, through the chamber 98, connecting channel 170, through the port 165, past the valve portion 166 and valve body 160, through the chamber 150, connecting channels 174 and 175 and the outlet 172, fitting 61, tube 62 and channels 64 and 66 for discharge through the fuel delivery orifice 40 into the air stream moving through the restricted region of the venturi 47.

Initial mixing of the fuel with air delivered from the pump chamber 22 of the air pump takes place in the region of the venturi 47, and additional air provided by the rotating impeller 76 flows through the openings 68 and is mixed with the fuel and air delivered from the venturi 47 to enhance more complete combustion, the burning gases moving through the sleeve 42 of burner construction shown in FIGURE 1.

Through this arrangement fuel is aspirated from the nozzle 40 only when an air stream is moving at high velocity adjacent the fuel delivery orifice 40 and the burner is in operation. In event of failure of air flow through the venturi, pressures are equalized at opposite sides of the diaphragms 94 and 142 and the normal biasing pressures of the springs 124 and 159 acting through their respective levers close both valves and 160.

The control unit illustrated in FIGURES 3 through 6 embodies several features which render the construction an effective control for a combustion burner where the fuel is aspirated into an air stream to provide a combustible mixture. From the standpoint of fire hazard, it is desirable that the valve seat 112 of the first inlet valve arrangement, that is, the valve arrangement first to receive fuel from the fuel line 56, be formed of metal and the valve body 110 be formed of metal. By fashioning the valve seat 112 of metal, the seat will not be impaired or subject to failure until the entire control unit is rendered ineffective by fire.

The valve seat 164 of the second valve arrangement in the unit may be fashioned of synthetic rubber or similar material or may be fashioned of metal. It is however desirable that the second valve seat 164 be formed of yieldable material, such as synthetic rubber, as the valve portion 166 of the valve body 160 tends to seat or seal tighter in a yieldable seat than a metal valve engaging a metal seat under normal operating conditions. It is to be understood however that both valve seats may be made of metal. The inlet valve bodies 110 and 160 may be made of stainless steel, brass or other suitable material.

In the control unit of the character described wherein the first valve seat 112 is fashioned of metal, a high factor of safety is provided against fire damage and where the second seat is fashioned of yieldable material such as synthetic rubber, the tendency is to attain improved sealing characteristics with the valve member.

Where metal valve seats are used they may be made of stainless steel or brass. The springs 124 and 159 for biasing the control valves 11% and 16th toward closed position may be made of brass or stainless steel to effectively close the valves even at comparatively high temperatures.

Another feature of the dual valve control unit is that in the event a foreign particle lodges between an inlet valve and its seat, the other inlet valve arrangement will effectively prevent fuel flow when the burner is not in operation. In installations where the fuel tank 54 is disposed above the burner, the progressive lowering of the fuel level during burner operation with the flow control unit has only a minor effect on the rate of delivery of the fuel.

In installations where the fuel tank 54 is above the burner, the gravity head or fuel pressure has little or no effect on fuel delivery at the nozzle. When aspiration or reduced pressure is effective in the fuel chambers 98 and 150, air pressure at the opposite sides of the diaphragms moves the diaphragms to open the fuel inlet valves 110 and 160 to permit fuel flow to the fuel delivery nozzle 40. The nozzle construction 40 presents some restriction to fuel flow and hence a fuel back pressure is built-up in the fuel chambers and flexing the diaphragms in the opposite direction allowing the springs to move the valves to reduce or shut off fuel flow.

This back pressure tending to close the inlet valves prevents flooding or over delivery of fuel from the nozzle 40 as the fuel back pressure arising by nozzle restriction is effective on the full area of the diaphragms, this force moving the diaphragms away from the levers 116 and 156, permits the expansive forces of the springs 124 and 159 to tend to close the inlet valves. Where the fuel tank is disposed with respect to the burner to provide a gravity head of fuel acting against the inlet valves, the varying gravity head as fuel is consumed is changed and the fuel pressure acting to open the inlet valves is likewise changed.

As the fuel level is reduced, the fuel pressure acting to open the inlet valve is likewise reduced. As this pressure of gravity head of fuel is reduced, the aspiration in chambers 98 and 150 increases slightly and the springs 124 and 159 are further compressed to allow the valves 110 and 160 to be further opened to compensate in a measure for the reduced gravity head.

In prior control arrangements for combustion burners of the general character described, it has been conven tional practice to employ a fuel bowl containing a floatcontrolled inlet valve which controls the delivery of fuel to a nozzle dependent upon the level of fuel in the fuel bowl, a change in the level of the fuel in the bowl influences the opening and closing of the inlet valve during burner operations, affecting variations in the rate of fuel delivered from the burner nozzle.

In the method of diaphragm control of this invention, the instant response of the diaphragm to differential pressures at opposite sides thereof provides effective control of fuel flow through the control unit.

The control unit of the invention provides a high degree of safety against fuel leakage and fire hazard. In the event of the failure of air flow at the fuel delivery nozzle irrespective of the relative position of the fuel tank with respect to the burner, pressures in the fuel chambers 98 and 150 are increased, causing the diaphragms to move in directions whereby the biasing forces of the springs 124 and 159, acting through the levers 116 and 156 immediately close the inlet valve members 110 and 160 to cut-off fuel flow from the fuel tank.

If there is a failure or fracture of a diaphragm, pressure in the adjacent fuel chamber is increased and equalized with the atmospheric pressure at the opposite side of the diaphragm and the spring immediately closes the inlet valve to prevent further delivery of fuel to the burner nozzle 40. A high factor of safety against fire hazard is attained through the control unit of the invention.

FIGURES 7 and 8 illustrate a modified fuel control construction of the invention wherein a single inlet valve is controlled by differential pressures on a diaphragm. The arrangement shown in FIGURES 7 and 8 includes a body member or housing 180 having a substantially annual portion 91a defining a fuel chamber 98a, a planar surface 920 forming a seat for an annular gasket 93a which is engaged by the peripheral region of an impervious flexible diaphargm 94a forming a flexible wall of the fuel chamber 98a. The diaphragm and gasket are secured in assembled relation with the housing 180 by a closure plate 595a secured to the housing 180 by screws 96a.

The central region of the closure plate 95a is recessed or shaped to provide an air space or chamber 99a accommodating flexing movements of the diaphragm 94a, the space 99a being vented to the atmosphere through a vent opening 100a in the closure plate 95a. The diaphragm 94a is reinforced at opposite sides 'by metal or discs 101a. The central axis or region of the diaphragm and the discs 101:: have aligned openings to accommodate a rivet 102a having a head or button 103a. The housing 180 is provided with a threaded bore receiving a tubular sleeve or valve guide member 109a in which is slidably mounted an inlet valve or valve member 110a having a cone-shaped valve portion 111a.

An annular valve seat member 112a is held in place by the sleeve 109a, an anular gasket 114a being disposed between the upper end of the guide sleeve 109a and the bottom of the bore accommodating the sleeve 109a. The annular valve seat 112a provides a port 115a cooperating with the valve portion 111a to control or regulate fuel flow into the fuel chamber 98a.

The lever 116a, disposed in the fuel chamber 981:, is fulcrumed on a pin 117a, the long arm 1118a of the lever being arranged to be engaged by the button 103a carried by the diaphragm, the short arm 120a of the lever being arranged to engage the valve member or body 110a. An exansive coil spring 124a normally exert-s pressure through the lever 116a biasing the inlet valve 110a toward the valve seat 112a to interrupt fuel flow through the inlet port 115a in the seat.

The housing 180 is provided with a 'boss portion 181 having a threaded inlet bore 126a to accommodate a fitting such as a fitting 106, shown in FIGURE 1, arranged at the end of a fuel conveying tube 56 connected with a tank 54 as shown in FIGURE 1. The inlet bore 126a is in communication with a bore 127a in the housing 180 through interconnecting passages 182 and 183. A portion of the bore 127a is threaded as at. 128a to accommodate a threaded plug 130a, the plug having a bore 131a to receive a cylindrically shaped fuel filter or screen 132a, the end of the screen being closed by a cup-shaped plug 133a.

The plug 130a is provided with a counterbore 134a and a peripheral recess 135a. Transverse openings 136a establish communication between the counterbore 134a and the peripheral recess 135a, the recess being in communication with the valve port 115a by a channel or duct 107a. The housing is fashioned with a threaded outlet bore 172a in communication with the fuel chamber 98a through interconnecting passages and 186. The outlet bore 172a is adapted to accommodate a fitting, such as fitting 61 shown in FIGURE 1, for conveying fuel from the chamber 98a to the fuel delivery nozzle 40 of the burner, shown in FIGURE 1.

The control unit, shown in FIGURES 7 and 8, is arranged to be connected in the fuel supply system, shown in FIGURE 1, in the same position as the unit 60. Fuel from the tank 54 is conveyed through the tube 56, fitting 106 and through the inlet bore 126a, interconnecting passages 182 and 183, through the screen or filter 132a, through the countenbore 134a, passages 136a and 107a and past the valve member 110a whenever aspiration at the burner nozzle is effective in the fuel chamber 98a to set up reduced pressure therein.

Such reduced pressure is effective through the outlet bore 172a and interconnecting passages 185 and 186 in the chamber 98a to cause the diaphragm to move or flex in a right-hand direction, as viewed in FIGURE 7.

Such movement of the diaphragm swings the lever 116a about its fulcrum 117a in a counterclockwise direction to permit the valve member 110a to move in a left-hand direction withdrawing the needle valve portion 111a from its seat to thereby effect fuel flow into the chamber 98a and its continued delivery to the fuel delivery nozzle 40 shown in FIGURE 1.

The filter 132a screens out foreign matter that may be in the liquid fuel to minimize the liability of foreign particles lodging on the valve seat 112a. In this form of control unit where a single diaphragm actuated valve controls fuel flow to the burner nozzle, the valve seat 112a should be made of metal, such as stainless steel or brass, to resist high temperatures and reduce liability of damage by fire.

It should be noted that the short arm 12011 of the lever is in contacting engagement with the valve so that when the diaphragm 94a is flexed, by aspiration or reduced pressure, in a right-hand direction, as viewed in FIGURE 7, the short arm of the lever moves in a left-hand direction and the valve member 110a is withdrawn under the influence of the reduced pressure in the chamber 98a to admit fuel flow past the inlet valve into the chamber. Thus, if the fuel tank 54, shown in FIGURE 1, is below the burner, the greater reduced pressure in the fuel chamber 98a causes the valve member 110a to be opened further.

If the fuel tank 54 is above the burner and a gravity head of fuel is existent in the channel 107a and the port 1150, the valve member 11011 will be influenced toward open position by the reduced pressure existent in chamber 98a under the influence of aspiration and, in addition, the gravity or pressure head of fuel on the inlet valve tends to move the valve toward open position.

Where a single diaphragm and inlet valve control mechanism is employed of the character shown in FIGURES 7 and 8, any impairment or failure of aspiration at the burner nozzle effects an increase in pressure in the chamber 980, the diaphragm is flexed in a lefthand direction, as viewed in FIGURE 7, and the spring 124a is effective through the lever 116a to close the fuel inlet valve 110a. In the event that the diaphragm 94a becomes fractured or impaired and pressure in the fuel chamber 98a is increased by air flow through a fracture in the diaphragm, the spring 1240 is automatically effective to close the fuel inlet valve 110a to interrupt fuel flow to the burner.

Thus, a single diaphragm and fuel inlet valve arrangement, shown in FIGURES 7 and 8, is effective to interrupt fuel flow except during burner operation when aspiration is effective on the fuel delivery nozzle 40. Fuel will only be delivered from the nozzle 40 when differential pressures are established at opposite sides of the diaphragrm 94a.

FIGURE 9 is a sectional view of a portion of the construction shown in FIGURE 7 illustrating a shackle connection between the lever and the valve and between the diaphragm button and the lever. In this form, the valve guide 10% in a bore in the housing 180 slidably accommodates an inlet valve member 1101). The diaphragm 94b is equipped with a rivet having a head 10312 fashioned with a tenon 191 which is straddled by the bifurcated or forked end of the long arm of a lever 190 fulcrumed on a pin 117b. The short arm 192 of the lever is bifurcated and the furcations straddle a tenon 193 formed by a recess in the valve member 110b, the recess in the valve member providing a head 194 on the valve 11%.

The shackle connection of the diaphragm button 10317 with the lever and the shackle connection of the short arm of the lever with the tenon 193 on the valve member provides a positive connection whereby movement of the lever 190 in either direction effects movement of the valve member 11012. In the event that a foreign particle lodges under the valve, fuel flowing into the fuel chamber increases the pressure which increases the valve-closing effort applied to the inlet valve through the lever. The valve member 11% is normally biased under the influence of an expansive coil spring 124b to engage the cone-shaped valve portion 111!) with the valve seat 11217.

The shackle connection, provided between the lever and the valve member, eliminates any tendency for the valve to stick in the valve seat. The arrangement of FIG- URE 9 operates in the same manner as the construction shown in FIGURE 7.

FIGURES 10 through 13 illustrate another form of dual valve construction for controlling fuel flow to a corn-bustion burner, the construction embodying a modified form of filter or strainer.

In this form the control unit includes a housing 200 similar to the housing 90, shown in FIGURE 5, formed with fuel chambers 980 and 1500, a wall of chamber 930 being provided by a flexible diaphragm 940, and a wall of the chamber 150a being provided by a flexible diaphragm 1420. Diaphragm 940 controls an inlet valve member 1100 through the lever 1160, the valve member 1100 being slidable in a valve guide 109a and is normally biased toward closed position under the influence of an expansive coil spring 1240.

The short arm of the lever 1160 is connected with the valve member 1100 by a shackle connection of the character shown in FIGURES 5, 6 and 9. The diaphragm 1420 controls the second valve member 1600 through the lever 1560, the valve member being slidable in a sleeve or valve guide 1620. A spring 1590 normally biases the valve member 1600 toward closed posiiton. The valvve members respectively cooperate with valve seats 1120 and 164c. It is preferable that the valve seat 1120 be formed of metal in order to resist high temperatures. The valve seat 1640 may be fashioned of metal or nonmetallic material such as synthetic rubber.

The diaphragm 94c is secured to the housing by a cover plate 950 secured in place by screws 960, a gasket being disposed between the housing and the diaphragm. The plate 950 is provided with a vent opening 1000. Disposed adjacent the diaphragm 14-20 is a circularly-shaped member 202 having a planar peripheral surface engaging the diaphragm 142c, a gasket being disposed between the housing 200 and the diaphragm, and the member 202 being secured to the housing 200 by means of screws 204.

The member 202 is fashioned with an annular chamber or region 206 which is in communication with a fuel duct or passage 208, the fuel passage 208 being in registration with a passage 210 formed in the housing 200. A short tube 211 is snugly fitted into the passage 210 to prevent fuel leakage in event of impairment of or damage to the diaphragm 1420 or the adjacent gasket. A vpassage 212 is drilled in the housing 200 and the outer end closed by a plug 214. The drill passage 212 is in communication with the port in the valve seat 1120 and with the passage 210 whereby fuel flows from the chamber 20-6 through passage 208, 210 and 212 to the region of the inlet valve 1100. The member 202 is fashioned with a central boss portion 216 fashioned with a ledge 217. The member 202 is provided with a circular recess 218, and disposed in the recess 218 and engaging the circular ledge 217 is a screen or filter 220 of fine mesh wire or other suitable filtering material. The member 202 is formed with a counter-bore adapted to accommodate a sealing gasket 222 which engages the peripheral region of a major surface of the screen 220. A circular closure member 224 has a surface 226 engaging the sealing gasket 222. The boss portion 216 is provided with a threaded bore to accommodate the threaded portion of a securing bolt 228 which extends through an opening in the member 224 and is adapted to secure the member 224 in snug engagement with the sealing gasket 222 to form a seal.

A seal gasket 229 is disposed adjacent the head of the bolt 228 to provide a liquid tight seal. The member 202 is shaped with a recess providing an air space 230 to accommodate flexing movements of the diaphragm 1420. The gaskets 222 and 229 are made of soft copper or other heat resistant material.

The space 230 is vented to the atmosphere through a vent means including a passage 232 in communication with a passage 233 opening into the air chamber 230, shown in FIGURE 12. The member 224 is provided with a threaded bore 235 in communication with a chamber 236 above the screen or filter 220 as shown in FIGURE ll.

The threaded bore 235 is adapted to accommodate an inlet fitting such as the fitting 106 shown in FIGURE 1 connected by a tube 56 with a fuel tank or fuel source. As shown in FIGURES 10 and 12, the housing or member 200 is provided with a threaded bore 238 which is in communication with the fuel chamber 1500 through a passage 239. The threaded bore 238 accommodates an outlet fitting such as the fitting 61 shown in FIGURE 1, which in turn is connected with the fuel delivery orifice 4-0 of a burner.

In the operation of the control unit shown in FIG- URES 10 through 13, aspiration or reduced pressure established adjacent the fuel delivery orifice of the burner is transmitted to the fuel chamber 1500 through passages 238 and 239. By reason of the establishment of differential pressures at opposite sides of the diaphragm 14210 the diaphragm is moved or flexed in a left-hand direction as viewed in FIGURE 11, pivoting the lever 1560 in a counterclockwise direction to move the valve member 1600 to open position. The port in the valve seat 1640 is in communication with the fuel chamber 980 through a passage 241.

Aspiration or reduced pressure is transmitted through the port in the valve seat 1640 and passage 241 to the fuel chamber 980. Reduced pressure in the fuel chamber 980 causes atmospheric pressure to flex the diaphragm 940 in a right-hand direction as viewed in FIGURE 11.

effecting counterclockwise pivotal movement of the lever 1160 to open the valve member 1100 by moving the valve member away from the valve seat 1120, admitting fuel from a fuel tank through communicating passageways 212, 210, 208, annular chambers 206 and 236, inlet 235 and fuel conveying tube 56, shown in FIGURE 1.

The incoming fuel from the tank fiows through the screen 220, past the valves 110c and 1600 in sequence and through the outlet 238 to the burner nozzle 40, shown in FIGURE 1. In the construction shown in FIG- URES through 13, the strainer and inlet passage arrangement is contained in the members 202 and 224, a construction which enables the use of a generally planar type of screen or filter 220.

FIGURES l4 and illustrate a further form of dual valve control mechanism in combination with a fuel filter or strainer of modified construction. In the construction shown in FIGURES 14 and 15 the dual valve mechanisms and their associated diaphragms are arranged in side-byside relation. The fuel flow control mechanisms are contained within an elongated housing 250 fashioned with spaced fuel chambers 252 and 254.

A flexible diaphragm component 255 forms a wall of the fuel chamber 252, and a second diaphragm component 257 forms a flexible wall of the second fuel chamber 254.

The diaphragm components 255 and 257 are illustrated as formed of a single member of impervious flexible material, such as synthetic rubber or flexible textile or cloth impregnated with an impervious coating, but it is to be understood that the diaphragm components 255 and 257 may be fashioned as two independent diaphragms. A gasket 259 is disposed between the peripheral regions of the diaphragm components and a planar upper surface area of the housing 250 to provide a seal between the housing and the diaphragms. A cover plate 260 embraces or covers both diaphragm components, the plate being secured to the housing 250 by screws 262.

As particularly illustrated in FIGURE 15, the plate 260 adjacent the diaphragms or diaphragm components 255 and 257 is fashioned with raised portions 264 and 266 providing chambers 269 and 270 to facilitate upward flexing movements of the diaphragms. The raised portions 264 and 266 are provided respectively with vent openings 267 and 268 whereby the spaces or chambers 269 and 270 are vented to the atmosphere.

The housing 250 is provided with a boss portion 272 having a threaded inlet bore 273 adapted to receive a component 274 of a union or coupling 275, The housing 250 is fashioned with a threaded bore accommodating a sleeve or valve cage 276 in which is slidably disposed an inlet valve or valve member 278.

The member 276 is fashoned with an inwardly extending flange or shoulder 279 defining an opening through which extends a stem portion 281 integrally formed on the valve 27 8.

The valve is provided with a cone-shaped valve portion adapted to engage the flange 279, the latter forming a seat for the cone-shaped valve portion. The lower end of member 276 engages a sealing gasket 283. The valve 278 is provided with an axial recess to accommodate an expansive. coil spring 286, the lower end of the spring engaging .in a recess 287 formed in the housing 250. A fuel channel hr passage 288 is formed in the housing in communication with the inlet bore 273 for conveying liquid fuel to the region adjacent the valve member 278.

The flexible diaphragm component 255 is flanked at each side with reinforcing discs 290 and a rivet 292 disposed centrally of the diaphragm and extends through aligned openings in the diaphragm and the reinforcing discs to secure the diaphragm component and reinforcing discs in assembled relation. The central axis of the diaphragm component 255 is aligned with the axis of the valve member 27 8 and its stem 281.

The end of the stem 281 is adapted to be engaged by the rivet 292 carried by the diaphragm whereby downwardly flexing movements of the diaphragm component 255 as viewed in FIGURE 15 moves the valve member 278 away from the valve seat 279 to facilitate flow of fuel upwardly past the valve member 278 and through the valve port defined by the ledge or seat 279 into the fuel chamber 252.

The arrangement is inclusive of a second valve construction adapted to be actuated or influenced by flexing movements of the second diaphragm component 257.

The second diaphragm component 257 is flanked at each side with reinforcing discs 294 secured to the diaphragm by a rivet 295. The housing 250 is provided with a threaded bore 293 accommodating a valve guide sleeve or cage 296, the axis of which is aligned with the rivet 295. Slidably disposed in the valve guide 296 is a valve 298 of the same construction as the valve 278. The hollow interior of the valve guide 296 is fashioned with an inwardly extending flange 300 which forms an abutment for an annular valve seat 302.

The valve seat 302 for the second valve 298 is preferably fashioned of synthetic rubber or other yieldable material which is engaged by a cone-shaped portion of the valve 298. The valve 298 is formed with a stern 304 arranged to be engaged by the rivet 295 whereby downward flexure or movement of the diaphragm. component 257 moves the valve 298 downwardly to open the port provided in the valve seat 302. The valve member 298 is formed with a recess accommodating an expansive coil spring 306, a recess 307 in the housing 250 accommodating the lower end of the spring 306.

The housing 250 is provided with a fuel passage or duct 308 in communication between the region adjacent the lower end of the valve 298 and the fuel chamber 252 adjacent the diaphragm component 255.

Liquid fuel in the chamber 252 is conveyed by duct 308 to a region adjacent the valve member 298 so that when the valve 298 is opened, fuel flows past the valve 298 into the second fuel chamber 254. A threaded outlet bore in the housing 250 is in communication with the fuel chamber 254 by a passage 312. The bore 310 accommodates a fitting 61, shown in FIGURE 1, whereby fuel is conveyed through the arrangement shown in FIGURE 1 connected with the fitting 61 to the burner nozzle 40.

The dual valve construction shown in FIGURES 14 and 15 is provided with a fuel filter or strainer construction to filter out foreign matter that may be in the liquid fuel. The fuel filter arrangement is inclusive of a body member 315 provided with a threaded inlet bore 317 which is adapted to accommodate a fitting, such as the fitting 106 shown in FIGURE 1 for connection with a fuel supply tube from a fuel tank. The body 315 is provided with a depending boss portion 318 fashioned with a circular ledge 319.

The body 315 is fashioned with a circular recess 320. A circular fine mesh screen or similar filter medium 322 has a central opening of a size whereby the screen seats against the ledge 319, the periphery of the screen fitting in the peripheral recess 320. An annular gasket 324 of nubber or other suitable sealing material engages the opposite peripheral surface of the screen 322, as shown in FIGURE 15. A cupshaped member 326 formed of metal is disposed beneath the body 315 and is fashioned with an outwardly extending peripheral flange 328 which engages the sealing gasket 324 fashioned of soft copper or suitable heat resistant material.

Depending from the cup-shaped member 326 is a circular collar-like portion 330 which engages in a recess of a member 332, the receses being defined by an inner flange 333 and an outer flange 334. The inner flange 333 defines a central threaded opening which receives a threaded member 335 provided at its lower end with a slot 336 which accommodates a wire bail 338. The bail 338 is of generally U-shaped configuration and has its end regions 339 bent to engage in recesses 340 formed in the upper portion of the housing 315 at diametrically arranged regions of the housing, as shown in FIG- URE 14.

The member 334-, having threaded engagement with the threaded member 335, is rotatable and may be manipulated to exert upward pressure upon the cup 326 to hold the flange 328 thereof in sealing engagement with the gasket 324. The cup-shaped member 326 may be removed for cleaning by rotating the member 332 in a direction to lower the member 332 out of engagement with the collar 330 depending from the cup 326. The threaded inlet bore 317 is in communication with a valve chamber 34-1, a counterbore 342 in the body 315 forming a seat or ledge 343 which is adapted to be engaged by a manually operable valve member 344 carried on a threaded valve stem 345, the latter having a manipulating handle 346.

A fitting 348 is threaded into a bore in the body 315 and is interiorly threaded to accommodate the threaded portion of the stem 34-5. A sealing gasket 350, secured in place by a retainer 351, engages the valve stem to prevent leakage of fuel along the stem.

When the valve stem is rotated in a direction to engage the valve 344 with the seat 343, fuel flow is interrupted into the fuel bowl 326. A passage 352 in the boss portion 318 is in communication with passage 342 for conveying liquid fuel from the supply into the bowl 326, the fuel flowing upwardly through the screen 322 and through the coupling 275 to the first control valve 278 in the housing 250.

In the construction shown in FIGURES 14 and 15, the diaphragms or diaphragm components 255 and 257 act directly upon the valves 278 and 298, and the expansive force of each of the springs 3% is preferably less than that of the springs employed with the motion transmitting lever constructions in the forms of the invention hereinbefore described so that the valves will be readily opened under the influence of aspiration or reduced pressure established adjacent the burner nozzle, shown in F IG- URE 1. It should be noted that the valve seat 302 is preferably made of rubber or yieldable material to obtain an effective seating engagement with the cone-shaped portion of the valve 298.

In the arrangement shown in FIGURES 14 and 15 and the constructions hereinbefore described wherein the control valves are normally biased toward closed position under the influence of springs or resilient means, the control units are operable in any position.

With the diaphragms arranged above the valves, as shown in FIGURE 15, the diaphragms are not subjected to the weight of fuel in the fuel chambers except when the arrangement is used in inverted position.

FIGURE 16 is a longitudinal sectional view of a dual valve construction similar to the construction shown in FIGURE 15 but without valve biasing springs. In the arrangement shown in FIGURE 16, the unit is positioned so that the diaphraigms are beneath the valves whereby the gravity head of fuel from the supply tank provides the biasing force for normally urging the valves toward closed position. The construction is inclusive of a housing 354 fashioned with fuel chambers 252 and 254', a flexible diaphragm component 255 forming a flexible wall of the chamber 252', and the flexible diaphragm component 257' forming a flexible wall of the fuel chamber 254, the diaphragms being flanked with reinforcing discs.

As in the construction shown in FIGURE 15, the diaphragm components are integrated of a single sheet of material, but it is to be understood that the diaphragm components may be independent members, if desired. The diaphragm components are held in place by a closure member 260' secured by screws 262'. The closure 260' is fashioned with raised portions 264 and 266' adjacent the regions of the diaphragms providing spaces 269' and 270' to accommodate flexing movements of the diaphragms, the portions 264' and 266 being vented through openings 267' and 268.

The housing 354 is formed with a threaded bore accommodating a valve guide member or cage 276' in which is slidably mounted a valve member 356. The axis of the valve 356 is aligned with the rivet 292 carried by the diaphragm component 255. The valve member 356 is provided with a stem 35"7 adapted to be directly engaged by the rivet 292' when the diaphrgam component 255' is flexed upwardly to move the cone-shaped valve portion of the valve 356 away from the annular valve seat 359 provided by a circular ledge 279' formed interiorly in the valve cage 276'.

The housing 354 is provided with a threaded inlet bore 362 in communication with a passage 363 adjacent the upper end of the valve 356. The inlet bore 362 is adapted to accommodate a fitting of the character shown at 106 in FIGURE 1 for connection with a fuel supply tube 56 connected with a fuel tank 54 as in FIGURE 1. In the form of control unit shown in FIGURE 16, the fuel tank is disposed above the unit whereby a gravity head of fuel is effective on the valve member 356 biasing the valve member toward closed position.

The housing 354 is formed with a second threaded bore accommodating a valve guide or cage 296 in which is slidably disposed a valve 365 provided with a coneshaped valve portion adapted to seat against an annular rubber seat 302' disposed adjacent an abutment 300' provided interiorly of the valve cage 296'.

The valve 365 is provided with a stem 367 adapted to be engaged by a rivet 295 carried by the diaphragm component 257. A chamber 368, at the upper end of the bore accommodating the valve guide 296, is connected with the fuel chamber 252 by a fuel passage or duct 369.

The housing 354 is provided with a threaded outlet duct 370 adapted to accommodate a fitting, such as fitting 61 shown in FIGURE 1, and the associated fuel conveying arrangement of FIGURE 1 for delivery of fuel to the burner nozzle 40. The outlet bore 370 is in communication with the chamber 254 by a passage 372. It should be noted that with the diaphragms or diaphragm components 255 and 257' disposed below the valve members and below the fuel supply tank, fuel in the passage 363 adjacent the valve 356 normally biases the valves toward closed positions when there is fuel in the unit.

In the operation of the arrangement shown in FIGURE 16, aspiration or reduced pressure at the fuel delivery nozzle 40 is transmitted through the passages 370 and 372 to the fuel chamber 254'. Reduced pressure therein effects upward movement of the diaphragm component 257', moving the valve member 365 away from its seat 302 whereby the reduced pressure is communicated to the fuel chamber 252' through the connecting passageway 369.

Reduced pressure in the fuel chamber 252' causes atmospheric pressure to flex the diaphragm component 255' upwardly, moving the valve 356 away from its seat 359 and permitting fuel to flow from the fuel tank through the inlet passages 362 and 363 'into the fuel chamber 252, thence through the channel 369, past the valve 365 into the fuel chamber 254" and through the outlet passage 370 for delivery through the main nozzle 40, shown in FIG- URE 1. As the fuel chambers 252 and 254' are unvented, fuel flow to the burner nozzle will continue only so long as reduced or differential pressure exists within the fuel chambers 252' and 254/.

In the event of failure of aspiration at the main nozzle, the pressure in the chambers 252' and 254' becomes atmospheric and the gravity head of the fuel causes the valve 356 to seat and interrupt fuel flow into the first chamber 252'. As the diaphragm 25-7 has moved downwardly by pressure equalization at opposite sides of this diaphragm, the valve member 365 engages the seat 302'. In the event of fracture of either of the diaphragm components 2-55 or 257, pressure is immediately equalized on opposite sides of the fracture diaphragm and the adjacent valve member will be closed by fuel pressure.

1 7 The arrangement shown in FIGURE 16 is adapted for effective use when the diaphragrns are in substantially horizontal positions and the valves in substantially vertiical positions and above the diaphragms in order that the gravity head or fuel pressure is effective to exert closing effort on the valves.

FIGURES 17 and 18 illustrate another form of liquid fuel control unit of the invention, this unit being of the I single inlet valve type. The unit includes a housing 376 having a circular portion 377 which is engaged by an annular sealing gasket 378, the annular region of a flexible diaphragm 379 engaging the gasket 378. A closure plate 380 holds the gasket and diaphragm in assembled relation and is secured to the body 37 6 by screws 381. The diaphrgam 379 is made of material which is impervious or coated to render it impervious.

The closure plate 380 is recessed or depressed adjacent the diaphragm to provide a space or air chamber 382 to accommodate flexing movements of the diaphragm, the space 382 being vented to the atmosphere through a vent opening 383 in the closure plate 380. The opposite sides of the diaphrgam 379 are flanked with reinforcing discs 384, the discs and diaphragm being held in assembled relation by a rivet 385 having a head or button 386. The circular portion 377 of the housing defines a fuel chamber 387 which is in communication with a threaded outlet bore 388 by communicating passages 389 and 390.

The housing or body 376 is fashioned with a boss 392 having a threaded inlet bore 393. The inlet bore 393 is in communication with a smooth bore 395 in the housing, the bore 395 slidably accommodating a valve or valve member 396 of polygonal cross section formed with a cone-shaped valve portion 397 and a valve stem 398.

The smooth bore 395 in the boss 392 terminates in an inwardly extending ledge or flange 399 which forms a seat for the valve portion 397, the flange defining an opening 400 through which extends the valve stem 398. Mounted in the fuel chamber 387 is a shaft or pin 402 which forms a fulcrum for one end of a lever 404.

The distal end of the lever is arranged to be engaged by the button 386 mounted by the diaphragm, the valve stem 398 engaging the lever at a region intermediate the lever fulcrum and the point of engagement of the lever with the diaphragm button 386. A perforated retainer or grid 405 is positioned in the bore 395 above the valve 396 to prevent dislodgement of the valve in an upward direction. In this form of the invention, the inlet fuel pressure provides the force normally biasing the valve 396 toward closed position. The inlet opening 393 receiver a fitting, such as fitting 106 shown in FIGURE 1, connected by a tube with 54 with a fuel supply.

Aspiration at the burner nozzle, such as nozzle 40 shown in FIGURE 1, is transmitted through the opening 388 and communicating passages 389 and 390 to the fuel chamber 387, the reduced pressure or differential pressure in the fuel chamber causes the diaphragm 379 to be raised upwardly by atmospheric pres-sure in the space 382. The button 386, engaging the lever 404, moves the lever in a counterclockwise direction about its fulcrum 402 elevating the valve member 396 away from its seat and permitting liquid fuel to flow past the valve member, through the opening 400 and through the fuel chamber 387 for delivery to the burner nozzle.

Failure of aspiration causes equalization of pressure at each side of the diaphragm and the weight of the valve member 396 together with the gravity head of incoming fuel perssure causes the valve portion 397 to engage its seat and interrupt fuel flow to the burner. The arrange ment shown in FIGURE 18 is adapted for use in the position wherein the valve 396 is in a vertical position above the diaphragm and with the fuel supply tank above the control unit in order to provide gravity head to close the valve member. If the diaphargm becomes fractured or the pressures become equalized on each side of the diaphragm,

the diaphragm returns to its normal position with the valve portion 397 engaging the valve seat 399 to interrupt fuel flow to the burner.

FIGURE 19 illustrates a construction similar to that shown in FIGURE 18 with a modified lever arrangement. The housing 409 is fashioned with an annular boss portion 377a formed with a planar surface on which is fitted a gasket 378a. The peripheral region of a flexible diaphragm 379a is disposed contiguous with the gasket 378a. A closure plate 380a engages the peripheral region of the diaphragm, the plate being secured to the housing 409 by screws 381a.

The central region of the closure plate 380a is recessed or depressed providing a space or air chamber 382a to accommodate flexing movements of the diaphragm 379a, the plate having a vent 383a open to the atmosphere.

Reinforcing discs 384a are disposed at opposite sides of the diaphragm and are secured to the diaphragm by a rivet 38511, the rivet having a head or button 386a. The annular portion 377a of the housing defines a fuel chamber 387a, the diaphragm 379a forming a wall of the chamber. The boss portion 392a is fashioned with a threaded inlet bore 39301 which is in communication with a smooth bore 395a of lesser diameter.

Slidably disposed in the smooth bore 395a is an inlet valve 396a having a cone-shaped valve lportion 397a terminating in a stern 398a. The valve portion 397a, seats against a ledge 399a defining an opening 400a accommodating the valve stem 398a. Mounted in the fuel chamber 387a is a shaft or pin 402a providing a fulcrum for a lever 408. The button or rivet head 386a mounted by the diaphragm is adapted to engage the lever 408 intermediate its ends.

The distal end of the lever 408 is adapted to engage the valve stem 398a. A perforated member or grid 405a is fixedly disposed in the upper end of the smooth bore 395a to prevent dislodgement of the valve member 396a. The housing 409 is fashioned with a threaded outlet bore 410 which is in communication with the fuel chamber 387a by connecting passages 411 and 412.

The control unit shown in FIGURE 19 functions in substantially the same manner as the unit shown in FIGURE 18. Aspiation or reduced pressure is transmitted from a burner nozzle such as nozzle 40 shown in FIGURE 1, through the outlet bore and passages 411 and 412 to the fuel chamber 387a.

Reduced pressure in the latter chamber causes atmospheric pressure to elevate the diaphragm 379a and move the valve member 396a to open position to admit fuel from a supply through the inlet bore 393a into the fuel chamber 3870: for delivery to the burner nozzle. In event of failure of aspiration or impairment or fracture of the diaphragm, the pressures at opposite sides of the diaphragm are equalized and the valve 396a closes under fuel pressure thereby preventing further flow of liquid fuel through the unit.

FIGURE 20 illustrates a control valve arrangement of the character shown in FIGURE 18 with a spring means for biasing the valve toward closed position. The boss portion 392 of the housing or body 376 has an inlet bore 393' in communication with a smooth bore 395', the valve member 396 being slidably mounted :in the bore 395. A grid or perforated member 405 is disposed above the valve and an expansive coil spring 407 is disposed between the grid and the valve member for exerting a resilient biasing force urging the valve toward closed position.

A spring may be embodied in the construction shown in FIGURE 19. When the construction shown in either of FIGURES 18 or 19 is modified as shown in FIGURE 20, with a spring biasing means for the valve, the control unit may be disposed in any position because the spring isetfective in any relative position to bias the valve closed.

FIGURE 21 illustrates another form of control unit of the invention. A housing or body member 415 is fashioned with a fuel chamber 416 defined by a circular portion 417. An annular gasket 418 is disposed on a planar sur- 

